In prior prefabricated house constructions, partition walls have been disposed with their upper portion projecting from the ceiling plane, and the ceiling panels have been sized to meet the dimension of a room. Thus, the inside dimension of the ceiling plane has seldom been an integer times a modular dimension because partition wall thicknesses tend to hinder a desired modular coordination. The use of reference-sized panels for ceiling assembly has been difficult. When deviation from modular coordination occurs, the outermost panel must be cut or modified at the house erection site. This increases labor costs and complicates the house assembly process.
In order to construct a ceiling assembly from reference panels, the dimensions of the ceiling plane as well as the panel units therefor must be held within fairly close tolerances during fabrication or the assembly of the panels is made more difficult. Furthermore, special consideration must be given to the provision of electrical wiring.